Hide start OPR button if OEMetadata is empty

[vismayajochem]

Description of the issue

If the metadata is empty, only one field is shown for the reviewer and the opr doesn't make much sense anyways.

Steps to Reproduce

1. Open an opr for an table with no metadata.

Ideas of solution

Hide the button to start an opr on the page of the table under Open Peer Review. Make the button conditional to not empty metadata.

Context and Environment

• Version used:
• Operating system:
• Environment setup and (python) version:

Workflow checklist

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